Portable backup power device



FIG. 1 is a perspective view of a portable backup power device showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is bottom plan view thereof; and,

FIG. 7 is a rear view thereof.

The broken lines showing are for illustrative purposes and form no part of the claimed design. 

The ornamental design for a portable backup power device, as shown and described. 